1. Field of the Invention
This invention relates, generally, to machines that insert sheets into envelopes at high speeds. More particularly, it relates to improvements in such machines in their envelope-opening mechanisms.
2. Description of the Prior Art
High speed machines for inserting sheets into envelopes generally include an envelope feed conveyor means for delivering envelopes to a hopper, means for sequentially removing the envelopes from the hopper, means for sequentially opening the envelopes, means for inserting sheets into the envelopes, and means for closing the envelopes and delivering them to a discharge table where they are bundled for mailing.
Typically, the envelopes travel in the same direction as the sheets.
The conventional means for opening an envelope includes a stationary blade-like member disposed in the path of an envelope as the envelope is transported from the hopper to a sheet insertion station. The blade-like member has no moving parts, i.e., it is passive in operation and simply deflects the flap of an envelope being pulled past it into an open position. When an envelope with an open flap arrives at the sheet insertion station, prior art machines include movably mounted suction cups that deploy, grasp the envelope, and hold the body of the envelope open while sheets are inserted thereinto.
In a co-pending disclosure, application Ser. No. 09/250,459 filed Feb. 16, 1999, by the same inventor, which is hereby incorporated by reference into this disclosure, the sheets and envelopes do not travel in the same direction. Instead, an envelope insertion table having a sheet insertion station is disposed at a right angle to the envelope inserting means. Horizontal airjets are used to puff open the main body of the envelope at the sheet insertion station, thereby eliminating the suction cups of the prior art.
However, a few problems remain. For example, a passive blade-like member, disposed between the envelope hopper and the sheet insertion station, sometimes fails to function satisfactorily because an envelope flap might be stuck in a closed position and the blade-like member thus may fail to get under the flap to deflect it into its open position. Thus, means for pre-opening the envelope are needed to improve the operation of the blade-like device.
Secondly, even if a flap is not stuck in a closed position, there are times when the blade fails to catch the flap correctly, and the desired deflection fails to occur. Thus, there is a need for an improved envelope flap deflection blade.
Moreover, although air jets are more satisfactory than reciprocating suction cups for holding the main body of the envelope open during sheet insertion, the leading end of an envelope will sometimes fail to open properly because a clamp used to pull the envelope through the machine will hold down the leading end of the envelope and thus at least partially defeat the action of the horizontal air jets. Accordingly, there is a need for an auxiliary means for opening the main body of the envelope at a sheet insertion station to augment the function of the air jets.
However, it was not obvious to those of ordinary skill in this art how the needed improvements could be provided, in view of the art considered as a whole at the time the present invention was made.
The long-standing but heretofore unfulfilled need for innovations that overcome the limitations of the prior art is now met by a new, useful, and nonobvious invention.
The invention includes an apparatus for at least partially pre-opening the flap of an envelope. The novel flap pre-opener forms a part of a machine for inserting sheets into envelopes; specifically, it is mounted on the edge of a table having a substantially horizontal support surface that supports envelopes as they are carried from a first station such as an envelope hopper to a second station such as a sheet insertion station. The envelope hopper or other suitable envelope alignment means aligns the envelopes relative to the support surface so that a flap-including longitudinal edge of the envelopes at least slightly overhang the edge of the table where the novel flap pre-opener is mounted as the envelopes travel from the envelope hopper to the sheet insertion station. In this way, said flap-including edges are constrained to pass through the flap pre-opener.
More particularly, the novel pre-opener includes a roller housing having an upwardly-opening channel formed therein within which a wheel is mounted for rotation in a vertical plane. The channel divides the roller housing into a table edge-abutting inboard part and an outboard part. The wheel is mounted such that its uppermost peripheral edge extends slightly above the plane of the support surface upon which an envelope is disposed in substantially horizontal disposition. The flap-including longitudinal edge of an envelope passing over the wheel is therefore lifted a small distance above said support surface by the wheel.
The roller housing includes a top part having a recess formed therein that is tapered downwardly from the direction of the envelope hopper to the sheet insertion station. The top part is positioned in closely spaced relation to the uppermost peripheral edge of the wheel on the outboard side of the roller housing. The recess is elevated to a first height at the entrance to the pre-opening station on the envelope hopper side of the pre-opener so that it does not interfere with the elevated edge of the envelope that is raised above the support surface by the wheel. The recess tapers downwardly toward the exit end of the pre-opener, constraining the edge of the envelope to bend downwardly at the same time the wheel is lifting the envelope near its outboard edge. This forms an arcuate curvature in the envelope back wall and causes the flap of the envelope to separate from said back wall. The separation provides an opening between the envelope back wall and flap into which a stationary flap-opening blade may enter as the envelope exits the pre-opener.
In another embodiment of the machine, the pre-opening of envelopes as they exit the envelope hopper is accomplished in the absence of the pre-opener just described. In this embodiment, a predetermined section of the support plate upon which the envelopes lie as they travel from the envelope hopper to a sheet insertion station is cut away so that the flap area of an envelope is not fully supported when it is in registration with said cut away. A stationary rigid deflector arm extends downwardly into the pathway of the flap area of the envelopes as they travel away from the envelope hopper, constraining the flap area to bend downwardly, below the plane of the support surface. This has essentially the same effect as the pre-opener described above. When the back of the envelope is deflected downwardly, the flap part thereof juts out therefrom, creating a space into which the stationary blade may enter.
This invention further includes an apparatus for holding open an envelope to facilitate insertion of a sheet therewithin, said apparatus also forming a part of a machine for inserting sheets into envelopes. The apparatus includes a modification to the above-mentioned support plate for supporting the back area of an envelope during a sheet insertion process. A plurality of longitudinally spaced apart recessed vacuum dishes are formed in the support plate, and each vacuum dish is in open fluid communication with a source of negative air pressure. The back wall (address side) of an envelope overlies the support plate during the sheet insertion process and each part of the address side of the envelope in registration with a vacuum dish is pulled downwardly when a negative pressure is applied to the vacuum dish. Accordingly, a space between the address side of the envelope and an opposing side thereof is widened when said parts of the address side are pulled downwardly, thereby facilitating insertion of a sheet into the envelope.
More particularly, the support plate within which the vacuum dishes are formed is made in two parts, one of which is stationary and one of which is slideably mounted. Both support plates lie in a common plane. A vacuum dish formed in the stationary part of the support plate is positioned so that it is in registration with a leading end of an envelope positioned at a sheet insertion station. A clamp that forms a part of a mechanism that sequentially pulls envelopes through the machine holds the leading end of the envelope. A plurality of longitudinally spaced apart vacuum dishes is formed in the slideably mounted support plate.
The novel apparatus includes a manifold means for delivering air under negative pressure from a vacuum source to each of the vacuum dishes. The manifold means includes flexible hoses that interconnect the vacuum source and the vacuum dishes so that the fluid communication between the vacuum source and the vacuum dishes is not lost when the slideably mounted support plate is displaced.
A short envelope is opened by a suction appearing at the stationary vacuum dish and by a suction appearing simultaneously at a first vacuum dish formed in the slideably mounted support plate, said first vacuum dish being nearest said stationary vacuum dish. A medium length envelope is opened by a suction appearing at the stationary vacuum dish and simultaneously at a second vacuum dish formed in the slideably mounted support plate, said second vacuum dish being spaced further from said stationary vacuum dish than said first vacuum dish formed in said slideably mounted support plate. A long envelope is opened by a suction appearing at the stationary vacuum dish and simultaneously at a third vacuum dish formed in the slideably mounted support plate, said third vacuum dish being spaced further from said stationary vacuum dish than said second vacuum dish. To accommodate still longer envelopes, the slideably mounted support plate is slid a preselected distance to a position further from the stationary support plate.
It is therefore understood that a primary object of this invention is to provide means for pre-opening an envelope flap to thereby enhance the performance of a conventional envelope flap-opening blade.
Another object is to provide an envelope pre-opener having no moving parts.
Another important object is to provide means for facilitating the opening of the main body of an envelope at a sheet insertion station.
These and other important objects, features, and advantages of the invention will become apparent as this description proceeds.
The invention accordingly comprises the features of construction, combination of elements and arrangement of parts that will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.